Lakeroadster's "T-Square" Rocket

[Steve Shannon]

I would not add the ballast or the fins. Although the thickness of the tail is not much, neither is it zero and there’s a long lever arm.

It’s easy to test. Take a t-square out and throw it. Does it end up flying tee forward?

 

[lakeroadster]

Definitely like the triangles at the bottom!

Not sure I understand adding 8 oz ballast to BOTTOM, I am not an open rocket guy, but seems counterintuitive.

Amazing drawings, although for you that is par for the course, as my Dad says.

Thanks.

I'm not sure I understand the weight issue either. Without 7 ounces of weight near the bottom of the rocket, running D12's, results in an error occurring during the Open Rocket simulation.

But with the F44's it's fine with or without the weight.

I would not add the ballast or the fins. Although the thickness of the tail is not much, neither is it zero and there’s a long lever arm.

It’s easy to test. Take a t-square out and throw it. Does it end up flying tee forward?

Agreed... no fins.

I've got my old T-Square from high school.... It's a museum piece... "Sir... step away from the T-Square or you'll meet Mr. Skillet"

 

[Daddyisabar]

It's bigger and now it's got exhaust headers!

Went back to the drawing board and increased the size of the model to allow use of some copper close radius pipe elbows to redirect the exhaust gasses.

The Open Rocket simulation was unstable until I lengthened the blade to 33-1/2" and added 8 oz of ballast to the bottom. Now she's right near purty again.

If I use Aerotek motors I could have used much smaller header pipes and probably gotten away with the previous T-Square model size, since the ejection nozzles are smaller on the Aerotech motors... but the D12's are more economical and a bigger rocket is mo 'betta. That being said... at a 222 ft apogee on D12's I'm not sure that will be enough altitude for the chutes to fully blossom?

What do you think?

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Now you are thinking more like a Grease Monkey (sorry, I mean rocket scientist,) so how are you going to deal with sealing the motor tube/casing to the header? Maybe a copper motor tube soldered to your header? Now that is thinking like a plumber, sorry, rocket scientist. Ejection charges are very hot and full of burning bits and hot kitty litter. How about a muffler or suppressor at the end of the pipe/barrel? Now that is thinking more like a gunsmith, sorry, rocket scientist. Anther piece of pipe with holes drilled downwards, all wrapped by lovely dog barf. The ultimate baffle! Now that is like STD Spock saying "I like science."

But then you need more power! Love them E12's. Love those 29mm F15's. Composites are harder to cluster but may become necessary. That is the power of Math people! MORE STD!

Weight up front good. Weight in back bad!

Reloads can tone down the force of the ejection charges! Would be better than single use. Still like using a red label BP motor too. Ejection charges scare me. My Jack in the Box ended up just using drag separation for deployment and it worked fine on that rocket. Hello Mr. RSO!

Also think of a no door design. Keep it simple. A friction fit or lightly taped chute could work better.

 

[lakeroadster]

Now you are thinking more like a Grease Monkey (sorry, I mean rocket scientist,) so how are you going to deal with sealing the motor tube/casing to the header?

Look at Dwg. Sheet #3, Section A-A and also the detail above the title block (re-posted below). It shows the header. The motor slides into the header and seats against the shoulder on the elbow. No place for the hot gases and bits to go but through the header.

Also think of a no door design. Keep it simple. A friction fit or lightly taped chute could work better.

Bombay doors.... gotta have bombay doors.. "Pilot to Bombardier.... Pilot to Bombardier... drop the laundry"

 

[jqavins]

It's "Mumbai doors" nowadays.

 

[Daddyisabar]

Motor retention?

 

[lakeroadster]

Motor retention?

The plan at this point is just the standard run of the mill spring clip.

 

[lakeroadster]

It's "Mumbai doors" nowadays.

"World History" for 300 Alex..

 

[Daddyisabar]

The plan at this point is just the standard run of the mill spring clip.

Just so it is strong enough to withstand the ejection recoil.

 

[jqavins]

A wrap of tape around the engine and hook together helps ensure it will hang on.

 

[lakeroadster]

Just so it is strong enough to withstand the ejection recoil.

Agreed. I thought about using smaller header pipes, but thought since they are as big as the motor it should minimize back pressure.

Another good reason for the bench test.

 

[Daddyisabar]

Mighty D motors are designed to pressurize a 4 inch tube about 3 feet long Saturn V-V2 Maxi Brute.